James Bottomley wrote:
Actually, it is surprising. That patch takes the default arithmetic for calculating the disk size out of sd and uses a routine to do it more efficiently in lib/string_helpers.c So there are two problems: Why does it panic on revert (could you post the oops) and what does kvm object to in string_get_size ... it's a fairly innocuous routine as I read it ... your symptoms sound like the for loop isn't terminating.
Here is the oops. Note that it does get well past the hang point before it crashes. It is 100% reproducible.
console [netcon0] enabled netconsole: network logging started Uniform Multi-Platform E-IDE driver ide-floppy driver 1.00 Driver 'sd' needs updating - please use bus_type methods scsi0 : ata_piix scsi1 : ata_piix ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc000 irq 14 ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc008 irq 15 ata1.00: ATA-7: QEMU HARDDISK, 0.9.1, max UDMA/100 ata1.00: 16777216 sectors, multi 16: LBA48 ata1.00: configured for MWDMA2 ata2.00: ATAPI: QEMU DVD-ROM, 0.9.1, max UDMA/100 ata2.00: configured for MWDMA2 scsi 0:0:0:0: Direct-Access ATA QEMU HARDDISK 0.9. PQ: 0 ANSI: 5 sd 0:0:0:0: [sda] 16777216 512-byte hardware sectors (8590 MB) sd 0:0:0:0: [sda] Write Protect is off sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA sd 0:0:0:0: [sda] 16777216 512-byte hardware sectors (8590 MB) sd 0:0:0:0: [sda] Write Protect is off sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA sda: sda1 sd 0:0:0:0: [sda] Attached SCSI disk scsi 1:0:0:0: CD-ROM QEMU QEMU DVD-ROM 0.9. PQ: 0 ANSI: 5 PNP: PS/2 Controller [PNP0303:KBD,PNP0f13:MOU] at 0x60,0x64 irq 1,12 serio: i8042 KBD port at 0x60,0x64 irq 1 serio: i8042 AUX port at 0x60,0x64 irq 12 mice: PS/2 mouse device common for all mice input: AT Translated Set 2 keyboard as /class/input/input0 md: linear personality registered for level -1 md: raid0 personality registered for level 0 md: raid1 personality registered for level 1 md: raid10 personality registered for level 10 raid6: int32x1 972 MB/s raid6: int32x2 1032 MB/s
raid6: int32x4 763 MB/s raid6: int32x8 729 MB/s raid6: mmxx1 2572 MB/s raid6: mmxx2 3154 MB/s raid6: sse1x1 2036 MB/s raid6: sse1x2 2430 MB/s raid6: sse2x1 3506 MB/s raid6: sse2x2 3428 MB/s raid6: using algorithm sse2x1 (3506 MB/s) md: raid6 personality registered for level 6 md: raid5 personality registered for level 5 md: raid4 personality registered for level 4 EDAC MC: Ver: 2.1.0 Oct 13 2008 input: ImExPS/2 Generic Explorer Mouse as /class/input/input1 dcdbas dcdbas: Dell Systems Management Base Driver (version 5.6.0-3.2) usbcore: registered new interface driver hiddev usbcore: registered new interface driver usbhid usbhid: v2.6:USB HID core driver TCP cubic registered NET: Registered protocol family 17 RPC: Registered udp transport module. RPC: Registered tcp transport module. Using IPI Shortcut mode registered taskstats version 1 BIOS EDD facility v0.16 2004-Jun-25, 1 devices found md: Autodetecting RAID arrays. md: Scanned 0 and added 0 devices. md: autorun ... md: ... autorun DONE. kjournald starting. Commit interval 5 seconds EXT3-fs: mounted filesystem with ordered data mode. VFS: Mounted root (ext3 filesystem) readonly. Freeing unused kernel memory: 304k freed Write protecting the kernel text: 3692k Write protecting the kernel read-only data: 1556k BUG: spinlock bad magic on CPU#0, swapper/1 lock: c0b75418, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0 Pid: 1, comm: swapper Not tainted 2.6.27 #17 Call Trace: [<c0597388>] ? printk+0xf/0x17 [<c03ac8ae>] spin_bug+0x75/0x80 [<c03ac97c>] _raw_spin_lock+0x1e/0xe4 [<c0412a3f>] ? serial8250_startup+0x33e/0x4e5 [<c0599821>] _spin_lock_irq+0x32/0x3a [<c0412a3f>] ? serial8250_startup+0x33e/0x4e5 [<c0412a3f>] serial8250_startup+0x33e/0x4e5 [<c040f5fb>] uart_startup+0x84/0x143 [<c0410309>] uart_open+0x14b/0x381 [<c05996ba>] ? _spin_unlock+0x27/0x3c [<c03f483f>] ? check_tty_count+0x3b/0x8a [<c03f70b9>] tty_open+0x263/0x366 [<c0271b2a>] chrdev_open+0x168/0x180 [<c026df19>] __dentry_open+0x146/0x234 [<c026e08e>] nameidata_to_filp+0x1f/0x33 [<c02719c2>] ? chrdev_open+0x0/0x180 [<c0278ed1>] do_filp_open+0x342/0x659 [<c023651c>] ? trace_hardirqs_off+0xb/0xd [<c05996ba>] ? _spin_unlock+0x27/0x3c [<c026dcff>] do_sys_open+0x42/0xb7 [<c026ddb6>] sys_open+0x1e/0x26 [<c0201216>] init_post+0x2a/0x13c [<c0203d53>] ? kernel_thread_helper+0x7/0x10 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
